Oscillating LDO regulator

[mono]

Garbz, I agree that ideally no data should be added but the card's driver doesn't allow 88.2. With this cheap card you take what you can get and in that respect I prefer the sound of 96 to 44.

Unfortunately after more really critical listening, the power supply on this card doesn't quite filter out all system noise. It does far far better than the card it replaced in that system but during heavy CPU load and drive activity I can still hear vary faint staticy-blip sorts of sounds.

Oddly I don't recall hearing that noise on my other AV-710, though it was never tried in same system and it sounds different anyway due to having the whole output stage gone, going straight from DAC to RCAs on the card, then a headamp.

 

[Garbz]

Is the card in the same slot? Could be inteference from somewhere else? In my experience unless there's a fault the PSU's regulation itself is not usually the first culprit.

 

[mono]

Quote:

Originally Posted by Garbz Is the card in the same slot? Could be inteference from somewhere else? In my experience unless there's a fault the PSU's regulation itself is not usually the first culprit.

Yes this card is in same slot, under a NIC. Added the NIC about 3 weeks ago, noise was there before NIC was. I'd tried the old sound card in another slot though, same thing (except the old one (Diamond Monster Sound (Vortex2 w/twin outputs, one with discrete output current stage) let even more of this noise through, but it might partly be because of the discrete output but not entirely, as I'd tried the other output with only voltage gain stage (TL074) too.

I hear these seemingly rail modulated power noises on many different systems with no common parts... different boards, CPUs, different high quality branded PSUs, integrated sound or sound card (but usually, it's far louder on integrated sound). I just assumed everyone was putting up with this noise in most cases? Is it a curse, that I have golden ears but they're only tuned to computer noises?

The noise mostly coincides with CPU load changes or HDD access, but on some systems, the CPU VRM board subcircuit isn't even sitting on the 12V rail so I can't quite isolate that either.

As a point of reference, one of the headamps used was a pretty much standard Pimeta, doesn't exhibit anything like this except hooked up to a computer (and it does have isolated DC power) but even without an amp I can hear it.

 

[Garbz]

Yeah now I know which sound you are talking about. My laptop exhibits it, although in that case it is a grounding error. I don't know why one would have it and not the other. Are all the unused inputs muted in the drivers?

 

[mono]

Quote:

Originally Posted by Garbz Yeah now I know which sound you are talking about. My laptop exhibits it, although in that case it is a grounding error. I don't know why one would have it and not the other. Are all the unused inputs muted in the drivers?

Yes, that's always the first thing I check.